1. Field of the Invention
This invention relates to a rudder propeller with an underwater transmission having a planetary gearing, the planetary gearing including a sun gear, a stationary ring gear, and planet gears mounted between the sun gear and ring gear and supported on planetary axles of a planet carrier.
2. Discussion of Related Art
Rudder propellers of the type mentioned above are known, for example, from German Patent Reference DE 28 43 459 A1. The rudder propeller is used to drive and control a watercraft. The engine torque of a drive motor, which is usually situated inside the watercraft, is transmitted by an above-water transmission via a drive shaft extending vertically downward to an underwater transmission, which usually includes an angle drive and a subsequent planetary gearing, from which the engine torque is finally transmitted to the horizontally extending propeller shaft, which supports the propeller. In order to control the watercraft, the underwater transmission is situated in a housing that can be rotated around the vertical axis.
Inside the planetary gearing, which reduces the speed of the drive motor, such as to a speed suitable for the propeller shaft, the roller bearing mounting of the planet gears that is standard in the prior art is critical because during operation of the rudder propeller, the bearings are subjected to significant loads, in particular alternating loads. The roller elements of the roller bearing mountings used therefore cannot run in optimal fashion and are susceptible to wear. Consequently, there are known proposals to use multilayer roller bearings in lieu of the roller bearing mountings of the planets on the planet axles, but this mounting is very cost-intensive.